flutter - for 循环出错：Flutter 中需要一个标识符
问题描述
我从列表中一一获取数字以使用telephony包发送短信，但在我的容器内，它给了我一个error at for loop. 请让我知道如何避免此错误
我的代码是：
import 'dart:async';
import 'package:epicare/Homepage.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:flutter_blue/flutter_blue.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:geolocator/geolocator.dart';
import 'package:telephony/telephony.dart';
class TriggeringAlert extends StatefulWidget {
const TriggeringAlert({Key key, this.device}) : super(key: key);
final BluetoothDevice device;
@override
_TriggeringAlertState createState() => _TriggeringAlertState();
}
class _TriggeringAlertState extends State<TriggeringAlert> {
// Get location
Position _currentPosition;
String _currentAddress;
final Geolocator geolocator = Geolocator()..forceAndroidLocationManager;
void initState(){
startTimer();
_getCurrentLocation();
getCaregivers();
super.initState();
}
Timer _timer;
int _start = 10;
void startTimer() {
if (_timer != null) {
_timer.cancel();
_timer = null;
} else {
_timer = new Timer.periodic(
const Duration(seconds: 1),
(Timer timer) => setState(
() {
if (_start < 1) {
timer.cancel();
} else {
_start = _start - 1;
}
},
),
);
}
}
_getCurrentLocation() {
geolocator
.getCurrentPosition(desiredAccuracy: LocationAccuracy.best)
.then((Position position) {
setState(() {
_currentPosition = position;
});
_getAddressFromLatLng();
}).catchError((e) {
print(e);
});
}
_getAddressFromLatLng() async {
try {
List<Placemark> p = await geolocator.placemarkFromCoordinates(
_currentPosition.latitude, _currentPosition.longitude);
Placemark place = p[0];
setState(() {
_currentAddress = "${place.locality}, ${place.country}";
});
} catch (e) {
print(e);
}
}
// Send SMS
final Telephony telephony = Telephony.instance;
sendSMS(String number) {
if (_currentPosition != null && _currentAddress != null)
print('Address $_currentAddress');
telephony.sendSms(
to: number,
message:
"This is to inform you that Epilepsy attack is occurring right now\n My current Location is: $_currentAddress",
);
}
User cuser = FirebaseAuth.instance.currentUser;
final fb = FirebaseDatabase.instance.reference().child("User_data");
List<String> numbers_list = List();
//Caregivers
void getCaregivers() {
// Firebase
fb
.child(cuser.uid)
.child("caregivers")
.once()
.then((DataSnapshot snapshot) {
var data = snapshot.value;
data.forEach((key, value) {
setState(() {
numbers_list.add(value['Caregiver_Number']);
});
});
});
}
@override
void dispose() {
_timer.cancel();
super.dispose();
}
@override
Widget build(BuildContext context) {
Size size = MediaQuery.of(context).size;
return Scaffold(
backgroundColor: const Color(0xffe8e5af),
body: Column(
children: [
Container(
width: size.width,
padding: EdgeInsets.only(top: 70),
child: Text(
'TRIGGERING ALERT IN',
style: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.w800,
fontSize: 21,
color: const Color(0xff000000),
height: 1.380952380952381,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Container(
width: size.width * 0.6,
padding: EdgeInsets.only(top: 21),
child: Text(
'If it is a false alarm please cancel the alert ',
style: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.w600,
fontSize: 15,
color: const Color(0xa8000000),
height: 1.3333333333333333,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Center(
child: Container(
//color: Colors.white,
height: size.height * 0.5,
alignment: Alignment.center,
//padding: EdgeInsets.only(bottom: 100),
child: Stack(
alignment:AlignmentDirectional.center,
children: [
Container(
//color: Colors.yellow,
padding: EdgeInsets.only(bottom:35),
child: Text(
'$_start',
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 50,
color: const Color(0xff000000),
letterSpacing: 5,
fontWeight: FontWeight.w600,
height: 0.7,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Container(
//color: Colors.yellow,
padding: EdgeInsets.only(top:45),
child: Text(
'Seconds',
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 14,
color: const Color(0xff000000),
letterSpacing: 1.4000000000000001,
fontWeight: FontWeight.w600,
height: 2.5,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Transform.scale(
scale: 5,
child: CircularProgressIndicator(
backgroundColor: const Color(0x26a4a67f),
strokeWidth: 2.0,
valueColor: AlwaysStoppedAnimation<Color>(Colors.black)),
),
],
),
),
),
SizedBox(
height: 90,
),
Container(
//padding: EdgeInsets.only(bottom: 85),
alignment: Alignment.center,
child: _start==0
? numbers_list.length == 0
? Fluttertoast.showToast(msg: "No caregivers")
:(
for (int i = 0; i < numbers_list.length; i++)
{
sendSMS(numbers_list[i].toString());
}
)
: ButtonTheme(
height: 50.0,
minWidth: 200.0,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(28)),
color: Colors.black,
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) {
return Homepage(device: widget.device,);
},
),
);
},
child: Text(
"Cancel Alert",
style: TextStyle(
fontSize: 14.0,
fontFamily: 'Montserrat',
color: const Color(0xffd4d411),
fontWeight: FontWeight.w700,
),
),
),
),
)
],
),
);
}
}
for循环的错误：
error: Expected to find ')'
error: Expected an identifier
解决方案
你可以试试这个：
基本上我所做的是将发送 SMS 的代码移动到你的startTimer()方法中，10 秒后，“取消警报”按钮将消失并被一个空的 SizedBox 取代。
import 'dart:async';
import 'package:epicare/Homepage.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:flutter/material.dart';
import 'package:flutter_blue/flutter_blue.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:geolocator/geolocator.dart';
import 'package:telephony/telephony.dart';
class TriggeringAlert extends StatefulWidget {
const TriggeringAlert({Key key, this.device}) : super(key: key);
final BluetoothDevice device;
@override
_TriggeringAlertState createState() => _TriggeringAlertState();
}
class _TriggeringAlertState extends State<TriggeringAlert> {
// Get location
Position _currentPosition;
String _currentAddress;
final Geolocator geolocator = Geolocator()..forceAndroidLocationManager;
void initState(){
startTimer();
_getCurrentLocation();
getCaregivers();
super.initState();
}
Timer _timer;
int _start = 10;
void startTimer() {
if (_timer != null) {
_timer.cancel();
_timer = null;
} else {
_timer = new Timer.periodic(
const Duration(seconds: 1),
(Timer timer) => setState(
() {
if (_start < 1) {
timer.cancel();
if (numbers_list.length == 0) Fluttertoast.showToast(msg: "No caregivers");
else {
for (int i = 0; i < numbers_list.length; i++) {
sendSMS(numbers_list[i].toString());
}
}
} else {
_start = _start - 1;
}
},
),
);
}
}
_getCurrentLocation() {
geolocator
.getCurrentPosition(desiredAccuracy: LocationAccuracy.best)
.then((Position position) {
setState(() {
_currentPosition = position;
});
_getAddressFromLatLng();
}).catchError((e) {
print(e);
});
}
_getAddressFromLatLng() async {
try {
List<Placemark> p = await geolocator.placemarkFromCoordinates(
_currentPosition.latitude, _currentPosition.longitude);
Placemark place = p[0];
setState(() {
_currentAddress = "${place.locality}, ${place.country}";
});
} catch (e) {
print(e);
}
}
// Send SMS
final Telephony telephony = Telephony.instance;
sendSMS(String number) {
if (_currentPosition != null && _currentAddress != null)
print('Address $_currentAddress');
telephony.sendSms(
to: number,
message:
"This is to inform you that Epilepsy attack is occurring right now\n My current Location is: $_currentAddress",
);
}
User cuser = FirebaseAuth.instance.currentUser;
final fb = FirebaseDatabase.instance.reference().child("User_data");
List<String> numbers_list = List();
//Caregivers
void getCaregivers() {
// Firebase
fb
.child(cuser.uid)
.child("caregivers")
.once()
.then((DataSnapshot snapshot) {
var data = snapshot.value;
data.forEach((key, value) {
setState(() {
numbers_list.add(value['Caregiver_Number']);
});
});
});
}
@override
void dispose() {
_timer.cancel();
super.dispose();
}
@override
Widget build(BuildContext context) {
Size size = MediaQuery.of(context).size;
return Scaffold(
backgroundColor: const Color(0xffe8e5af),
body: Column(
children: [
Container(
width: size.width,
padding: EdgeInsets.only(top: 70),
child: Text(
'TRIGGERING ALERT IN',
style: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.w800,
fontSize: 21,
color: const Color(0xff000000),
height: 1.380952380952381,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Container(
width: size.width * 0.6,
padding: EdgeInsets.only(top: 21),
child: Text(
'If it is a false alarm please cancel the alert ',
style: TextStyle(
fontFamily: 'Montserrat',
fontWeight: FontWeight.w600,
fontSize: 15,
color: const Color(0xa8000000),
height: 1.3333333333333333,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Center(
child: Container(
//color: Colors.white,
height: size.height * 0.5,
alignment: Alignment.center,
//padding: EdgeInsets.only(bottom: 100),
child: Stack(
alignment:AlignmentDirectional.center,
children: [
Container(
//color: Colors.yellow,
padding: EdgeInsets.only(bottom:35),
child: Text(
'$_start',
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 50,
color: const Color(0xff000000),
letterSpacing: 5,
fontWeight: FontWeight.w600,
height: 0.7,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Container(
//color: Colors.yellow,
padding: EdgeInsets.only(top:45),
child: Text(
'Seconds',
style: TextStyle(
fontFamily: 'Montserrat',
fontSize: 14,
color: const Color(0xff000000),
letterSpacing: 1.4000000000000001,
fontWeight: FontWeight.w600,
height: 2.5,
),
textHeightBehavior:
TextHeightBehavior(applyHeightToFirstAscent: false),
textAlign: TextAlign.center,
),
),
Transform.scale(
scale: 5,
child: CircularProgressIndicator(
backgroundColor: const Color(0x26a4a67f),
strokeWidth: 2.0,
valueColor: AlwaysStoppedAnimation<Color>(Colors.black)),
),
],
),
),
),
SizedBox(
height: 90,
),
Container(
//padding: EdgeInsets.only(bottom: 85),
alignment: Alignment.center,
child: _start == 0
? SizedBox.shrink()
: ButtonTheme(
height: 50.0,
minWidth: 200.0,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(28)),
color: Colors.black,
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) {
return Homepage(device: widget.device,);
},
),
);
},
child: Text(
"Cancel Alert",
style: TextStyle(
fontSize: 14.0,
fontFamily: 'Montserrat',
color: const Color(0xffd4d411),
fontWeight: FontWeight.w700,
),
),
),
),
)
],
),
);
}
}
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